Apply a redirect, and create a new url tree

applyRedirectCreateUrlTree.ts

private applyRedirectCreatreUrlTree(
    redirectTo: string, urlTree: UrlTree, segments: UrlSegment[],
    posParams: {[k: string]: UrlSegment}): UrlTree {
  const newRoot = this.createSegmentGroup(redirectTo, urlTree.root, segments, posParams);
  return new UrlTree(
      newRoot, this.createQueryParams(urlTree.queryParams, this.urlTree.queryParams),
      urlTree.fragment);
}